1. Technical Field
The present disclosure relates generally to systems and methods for spooling and unspooling linear material and, in particular, to a motorized device having a controller for controlling the spooling and/or unspooling of linear material.
2. Description of the Related Technology
Linear material, such as hoses, cords, cables, and the like, can be cumbersome and difficult to manage. Reels and like mechanical devices have been designed to help unspool such linear material from a rotatable spool member or a drum-like apparatus from which it can be deployed and wound upon. Some conventional devices are manually operated, requiring the user to physically rotate the spool member or drum to spool (wind in) the linear material and to pull, without any assistance, when unwinding. This can be tiresome and time-consuming for users, especially when the material is of a substantial length or is heavy, or when the drum or spool member is otherwise difficult to rotate. Other devices are motor-controlled, and can automatically wind in the linear material. These automatic devices often have a gear assembly wherein multiple revolutions of the motor produce a single revolution of the spool member or drum. For example, some conventional automatic devices have a 30:1 gear reduction, wherein 30 revolutions of the motor result in one revolution of the spool member or drum.
However, when a user attempts to pull out the linear material from such a geared device, the user must pull against the increased resistance caused by the gear reduction because the motor spins a number of times for every full revolution of the drum or spool member. Not only does this place an extra physical burden on the user (over and above the burden to unwind a possibly heavy linear material wound on a possibly heavy drum), but the linear material also experiences additional strain because it must withstand the stress of the user pulling on it with a pulling force sufficient force to overcome the increased resistance. Some automatic devices include a clutch system, such as a neutral position clutch, that neutralizes (or de-clutches) the motor to enable the user to freely pull out the linear material. This often requires the user to be at the site of the device to activate the clutch. In addition, clutch assemblies can be expensive and substantially increase the cost of automatic devices. Furthermore, they do not address the issue of the resistance due to the weight of the linear material and the rotational inertia of the drum.
On the other hand, once a user has initiated unwinding of the linear material and overcome the initial resistance, the drum, motor, and linear material will have momentum that will tend to cause continued unspooling even after the user has stopped pulling. This continued unspooling can lead to kinks, undesired slack, and other undesirable results. Some systems include a mechanical brake that engages when the user stops putting tension on the linear material by reacting directly to tautness in the linear material, but such solutions are not necessarily appropriate when the unwinding can be powered by a motor as well as user supplied tension, and generally do not account for scenarios where a user is walking while holding the linear material and/or when natural arm swing causes repeated rising and falling tension.
Also, when linear material is unwound from such a device by pulling it, if the proximal end portion of the linear the material (i.e., the end coupled to the rotatable spool member) is unwound, there is a risk of fatigue, leakage, joint damage, and related or similar issues where the linear material is attached to the device. It is also desirable that such a system address this issue.
Moreover, existing methods of unwinding linear material have encountered issues related to controlling the unwinding of linear material while linear material is unwound from a spool member. Additionally, the linear material experiences significant stress and strain as users repeatedly pull it from the reel, which can result in damage to the linear material. Furthermore, some existing methods of unwinding linear material have consumed significant power. Accordingly, a need exists for improved unwinding of linear material to address one or more of these issues, among others.
In addition, some existing methods of winding linear material have encountered problems related to winding an end portion of the linear material around a spool member. Moreover, in some existing methods of winding linear material, suspending the winding of linear material has been implemented substantially the same way for all circumstances, rather than customizing when winding is suspended based on winding conditions. Accordingly, a need exists for improved winding of linear material to address one or more of these issues, among others.
For the purposes of addressing these issues and for other reasons, it is often desirable to know how much material has been unwound from such a device, how much material remains spooled, or when or if a threshold amount of material has been unwound or remains spooled.